Add UTF-8 validation fast paths in `Wtf8Buf`
This adds two more fast paths for UTF-8 validation in `Wtf8Buf`, making use of the `is_known_utf8` flag added in https://github.com/rust-lang/rust/pull/96869 (Optimize `Wtf8Buf::into_string` for the case where it contains UTF-8).
r? `@ChrisDenton`
Rollup of 8 pull requests
Successful merges:
- #137370 (adjust_abi: make fallback logic for ABIs a bit easier to read)
- #137444 (Improve behavior of `IF_LET_RESCOPE` around temporaries and place expressions)
- #137464 (Fix invalid suggestion from type error for derive macro)
- #137539 ( Add rustdoc-gui regression test for #137082 )
- #137576 (Don't doc-comment BTreeMap<K, SetValZST, A>)
- #137595 (remove `simd_fpow` and `simd_fpowi`)
- #137600 (type_ir: remove redundant part of comment)
- #137602 (feature: fix typo in attribute description)
r? `@ghost`
`@rustbot` modify labels: rollup
Don't require method impls for methods with `Self:Sized` bounds for impls for unsized types
Similarly to how #112319 doesn't require specifying associated types with `Self: Sized` bounds on `dyn Trait`, we now don't require assoc items with `Self: Sized` bounds to be in impls of for unsized types.
Additionally we lint assoc items with `Self: Sized` bounds that are in such impls:
```rust
trait Foo {
fn foo() where Self: Sized;
}
impl Foo for () {
fn foo() {}
}
impl Foo for i32 {}
//~^ ERROR: not all trait items implemented, missing: `foo`
impl Foo for dyn std::fmt::Debug {}
#[deny(dead_code)]
impl Foo for dyn std::fmt::Display {
fn foo() {}
//~^ ERROR this item cannot be used as its where bounds are not satisfied
}
```
Note that this works with the same `Self: Sized` specific logic we already have for `dyn Trait`, so no new capabilities like avoiding assoc items with `Self: Copy` bounds on impls for `String` or such are added here. Specifying `where ConcreteType: Sized` in a trait and implementing the trait for `ConcreteType` also does not work, it *must* be exactly `Self: Sized`.
remove `simd_fpow` and `simd_fpowi`
Discussed in https://github.com/rust-lang/rust/issues/137555
These functions are not exposed from `std::intrinsics::simd`, and not used anywhere outside of the compiler. They also don't lower to particularly good code at least on the major ISAs (I checked x86_64, aarch64, s390x, powerpc), where the vector is just spilled to the stack and scalar functions are used for the actual logic.
r? `@RalfJung`
Don't doc-comment BTreeMap<K, SetValZST, A>
This otherwise shows up in documentation as an empty impl block (worse, at the *top* of the docs above the public impls).
Add rustdoc-gui regression test for #137082
Fixes https://github.com/rust-lang/rust/issues/137082.
Added new commands in `browser-ui-test` allowing us to add a regression test for #137082 and also another to copy code examples content.
r? `@notriddle`
Improve behavior of `IF_LET_RESCOPE` around temporaries and place expressions
Heavily reworks the `IF_LET_RESCOPE` to be more sensitive around 1. temporaries that get consumed/terminated and therefore should not trigger the lint, and 2. borrows of place expressions, which are not temporary values.
Fixes#137411
Make `#[used]` work when linking with `ld64`
To make `#[used]` work in static libraries, we use the `symbols.o` trick introduced in https://github.com/rust-lang/rust/pull/95604.
However, the linker shipped with Xcode, ld64, works a bit differently from other linkers; in particular, [it completely ignores undefined symbols by themselves](https://github.com/apple-oss-distributions/ld64/blob/ld64-954.16/src/ld/parsers/macho_relocatable_file.cpp#L2455-L2468), and only consider them if they have relocations (something something atoms something fixups, I don't know the details).
So to make the `symbols.o` file work on ld64, we need to actually insert a relocation. That's kinda cumbersome to do though, since the relocation must be valid, and hence must point to a valid piece of machine code, and is hence very architecture-specific.
Fixes https://github.com/rust-lang/rust/issues/133491, see that for investigation.
---
Another option would be to pass `-u _foo` to the final linker invocation. This has the problem that `-u` causes the linker to not be able to dead-strip the symbol, which is undesirable. (If we did this, we would possibly also want to do it by putting the arguments in a file by itself, and passing that file via ``@`,` e.g. ``@undefined_symbols.txt`,` similar to https://github.com/rust-lang/rust/issues/52699, though that [is only supported since Xcode 12](https://developer.apple.com/documentation/xcode-release-notes/xcode-12-release-notes#Linking), and I'm not sure we wanna bump that).
Various other options that are probably all undesirable as they affect link time performance:
- Pass `-all_load` to the linker.
- Pass `-ObjC` to the linker (the Objective-C support in the linker has different code paths that load more of the binary), and instrument the binaries that contain `#[used]` symbols.
- Pass `-force_load` to libraries that contain `#[used]` symbols.
Failed attempt: Embed `-u _foo` in the object file with `LC_LINKER_OPTION`, akin to https://github.com/rust-lang/rust/issues/121293. Doesn't work, both because `ld64` doesn't read that from archive members unless it already has a reason to load the member (which is what this PR is trying to make it do), and because `ld64` only support the `-l`, `-needed-l`, `-framework` and `-needed_framework` flags in there.
---
TODO:
- [x] Support all Apple architectures.
- [x] Ensure that this works regardless of the actual type of the symbol.
- [x] Write up more docs.
- [x] Wire up a few proper tests.
`@rustbot` label O-apple
Update books
## rust-lang/book
2 commits in d4d2c18cbd20876b2130a546e790446a8444cb32..4a01a9182496f807aaa5f72d93a25ce18bcbe105
2025-02-24 14:48:34 UTC to 2025-02-13 19:29:47 UTC
- Fix typos in chapter 17 (rust-lang/book#4238)
- NoStarch backports (rust-lang/book#4224)
## rust-lang/edition-guide
2 commits in 8dbdda7cae4fa030f09f8f5b63994d4d1dde74b9..daa4b763cd848f986813b5cf8069e1649f7147af
2025-02-22 14:58:51 UTC to 2025-02-21 02:30:17 UTC
- Remove precise capturing features (rust-lang/edition-guide#362)
- use same name as previous example (rust-lang/edition-guide#360)
## rust-lang/nomicon
1 commits in 336f75835a6c0514852cc65aba9a698b699b13c8..8f5c7322b65d079aa5b242eb10d89a98e12471e1
2025-02-19 13:16:47 UTC to 2025-02-19 13:16:47 UTC
- other-reprs: do not make it sound like we are making ABI promises for repr(int) enums (rust-lang/nomicon#461)
## rust-lang/reference
4 commits in 6195dbd70fc6f0980c314b4d23875ac570d8253a..615b4cec60c269cfc105d511c93287620032d5b0
2025-02-18 23:01:53 UTC to 2025-02-13 15:12:49 UTC
- Add rule identifiers to names chapters (rust-lang/reference#1737)
- Switch from AVX to SSE in the example (rust-lang/reference#1735)
- Remove attributes from struct field rest patterns (rust-lang/reference#1736)
- Update reference for target_feature_11. (rust-lang/reference#1720)
Don't immediately panic if dropck fails without returning errors
This span_bug was a little too optimistic. I've decided that matching on the ErrorGuaranteed is a little more sensible than a delay bug that will always be ignored.
closes#137329
r? `@compiler-errors`
remove `#[rustc_intrinsic_must_be_overridde]`
In https://github.com/rust-lang/rust/pull/135031, we gained support for just leaving away the body. Now that the bootstrap compiler got bumped, stop using the old style and remove support for it.
r? `@oli-obk`
There are a few more mentions of this attribute in RA code that I didn't touch; Cc `@rust-lang/rust-analyzer`
Consolidate and improve error messaging for `CoerceUnsized` and `DispatchFromDyn`
Firstly, this PR consolidates and reworks the error diagnostics for `CoercePointee` and `DispatchFromDyn`. There was a ton of duplication for no reason -- this reworks both the errors and also the error codes, since they can be shared between both traits since they report the same thing.
Secondly, when encountering a struct with multiple fields that must be coerced, point out the field spans, rather than mentioning the fields by name. This makes the error message clearer, but also means that we don't mention the `__S` dummy parameter for `derive(CoercePointee)`.
Thirdly, emit a custom error message when we encounter a trait error that comes from the recursive field `CoerceUnsized`/`DispatchFromDyn` trait check. **Note:** This is the only one I'm not too satisfied with -- I think it could use some more refinement, but ideally it explains that the field must be an unsize-able pointer... Feedback welcome.
Finally, don't emit `DispatchFromDyn` validity errors if we detect `CoerceUnsized` validity errors from an impl of the same ADT.
This is best reviewed per commit.
r? `@oli-obk` perhaps?
cc `@dingxiangfei2009` -- sorry for making my own attempt at this PR, but I wanted to see if I could implement a fix for #136796 in a less complicated way, since communicating over github review comments can be a bit slow. I'll leave comments inline to explain my thinking about the diagnostics changes.
Remove `feature(dyn_compatible_for_dispatch)` from the compiler
This PR proposes the removal of `feature(dyn_compatible_for_dispatch)` from the compiler.
* As far as I can tell from the tracking issue, there's very little demand for this feature. I think that if this feature becomes useful in the future, then a fresh implementation from a fresh set of eyes, with renewed understanding of how this feature fits into the picture of Rust as it exists **today** would be great to have; however, in the absence of this demand, I don't see a particularly good reason to keep this implementation around.
* The RFC didn't receive very much discussion outside of the lang team, and while the discussion it received seemed to suggest that this feature was aiming to simplify the language and improve expressibility, I don't think this feature has really demonstrated either of those goals in practice. Furthermore, nobody seems to have owned this feature for quite some time or express desire to push for its stabilization.
* Relatedly, I find some of the RFC discussion like "when we make things impossible it's often presumptuous"[^1] and "I tend to want to take a 'we are all adults here' attitude toward unsafe code"[^2] to be particularly uncompelling. Of course this is no criticism to the authors of those comments since they're pretty old comments now, but type soundness is (IMO) the primary goal of the types team. This feature doesn't really do much other than further complicating the story of where we must validate object safety for soundness, along making dyn-incompatible trait object types *almost* seem useful, but very much remain UB to create and misleading to users who don't know better.
* Dyn compatibility's story has gotten more complicated since the feature was proposed in 2017, and now it needs to interact with things like associated consts, GATs, RPITITs, trait upcasting, `dyn*`, etc. While some of this is exercised in the codebase today, I'm not confident all of the corners of this feature have been hammered out. Reducing the "surface area" for what can go wrong in the compiler, especially around a side of the language (`dyn Trait`) that has been known to be particularly unsound in the past, seems good enough motivation to get rid of this for now.
[^1]: https://github.com/rust-lang/rfcs/pull/2027#issuecomment-307592857
[^2]: https://github.com/rust-lang/rfcs/pull/2027#issuecomment-307645838
cc `@rust-lang/types` `@rust-lang/lang`
Tracking:
- #43561
r? types
remove some unnecessary rustc_const_unstable
If the function is anyway unstable, it doesn't need to be `rustc_const_unstable`.
`copy_from_slice` turns out to not do anything const-unstable itself, we just haven't stably committed to it being available in const yet. See [here](https://rustc-dev-guide.rust-lang.org/stability.html?highlight=rustc_const_stable_indirect) for more details on the `rustc_const_stable_indirect` attribute.
configure.py: don't instruct user to run nonexistent program
```shell-session
$ ./configure
configure: processing command line
configure:
configure: build.configure-args := []
configure: profile := dist
configure:
configure: writing `config.toml` in current directory
configure:
configure: run `python /mnt/filling/store/nabijaczleweli/code/rust/x.py --help`
```
This is naturally not valid since I don't have a "python" executable (and this will hopefully become more and more true as Python 2 dies out).
./configure knows this since it does `try python3 "$``@"`,`` then `python2.7` &c.
After, this now says
```
configure: run `python3 /mnt/filling/store/nabijaczleweli/code/rust/x.py --help`
```
which is possible, and corresponds to the interpreter actually running.
Implement `read_buf` for zkVM stdin
For the zkVM, even when a guest buffer is uninitialized, from the host's perspective it is just a normal piece of memory which was initialized before letting the guest write into it. This makes `sys_read` safe to use with an uninitialized buffer. See https://github.com/risc0/risc0/issues/2853.
cc `@bobbobbio,` `@flaub`
r? `@Noratrieb`
Tracked in https://github.com/rust-lang/rust/issues/136756
